1. Field of Invention
This invention relates to a method and apparatus for manufacturing a bulky, soft and absorbent paper web.
2. Description of the Prior Art
U.S. patent application Ser. No. 933,203 Hulit, et al., filed Aug. 14, 1978, relates to a system for producing a bulky, soft and absorbent paper web using mechanical means to predry the web. The structure for predrying the web includes a papermaker's felt and imprinting fabric of a specific character and a pair of opposed rolls creating a compression nip defined by the fabric and felt through which the web is passed and partially dewatered. According to the aforesaid application, the web prior to entering the fabric-felt compression nip is essentially uncompacted and the fabric-felt arrangement comprises the initial predrying stage in the system. Since the imprinting fabric then carries the predried web in undisturbed condition to a Yankee dryer or other component defining a heated drying surface, the only significant compacting of the web that occurs in the system of the aforesaid application is at the location of the compaction elements or knuckles of the imprinting fabric. As a consequence, a soft, bulky and absorbent sheet is produced through use of the system covered thereby.
U.S. patent application Ser. No. 280,752, R. E. Hostetler, filed July 6, 1981, also relates to a system for producing a bulky, soft and absorbent paper web. In accordance with the teachings of this latter application a wet web of principally lignocellulosic fibers is positioned on a first dewatering felt and then conveyed by the felt through a first nip formed by it and a second dewatering felt to remove water from the web. The partially dewatered web is then conveyed to a second nip formed between a dewatering felt and an open mesh imprinting fabric formed of woven filaments, the fabric having spaced compaction elements and defining voids between the filaments. While the partially dewatered web is in the second nip, it is impressed against the fabric by the felt to force a predetermined portion of the web into the voids and provide bulk thereto. The web is then retained on the imprinting fabric after the web passes through the second nip and removed therefrom before final drying by applying the web to a creping surface at a third nip location, the third nip being formed between the creping surface and the imprinting fabric. The web is retained on the imprinting fabric in an essentially undisturbed condition during retention and transport thereof on the imprinting fabric between the second and third nips.